The proposed program project will study various aspects of the molecular and cellular biology of the basement membrane zone of the skin. The goals of this project focus on characterizing candidate proteins of potential importance in pathophysiologic events involved in epidermolysis bullosa (EB). We shall attempt to define structures and proteins involved in the functional integrity of the basement membrane zone and to characterize mechanisms governing their synthesis, secretion and degradation. The specific projects are as follows. I. "Development and Use of DNA Clones for Candidate Proteins of Potential Importance in Recessive Dystrophic, Recessive Junctional, and Acquired EB" will develop and use probes to map genes and establish polymorphisms in hereditary EB and define possible relationships between acquired EB and HLA. II. "Keratinocyte Locomotion and Protease Expression" will examine the attachment and migratory behavior of keratinocytes and characterize the repertoire of matalloproteases expressed by the migrating cells. III. "Development of Model Systems for BMZs: Metabolism of the Dermal Microvascular Basement Membrane" will examine matrix protein synthesis by normal and activated endothelial cells and compare the behavior of these cells with that of endothelial cells from patients with EB. IV. "Chronic Injury, Enhanced Proteolysis and Carcinogenesis in RDEB" is predicated on the notion that excessive proteolysis is fundamental to understanding the connective tissue destruction that characterizes RDEB. It will explore the mechanisms of regulation of matalloprotease expression in a 3-dimensional model of reconstituted skin. In addition, in an attempt to understand the basis for an increased propensity to develop skin cancers in RDEB, RDEB skin as a xenograft will be examined for carcinogenic potential. V. "The Fetal Wound Response" will characterize the expression in fetal skin of certain key proteins and antigens of the basement membrane zone during fetal development. The behavior of fetal skin grafted onto nude or SCID mice will be determined and compared to the wound response of EB skin similarly engrafted. VI. "Biology of the Interaction of Keratinocytes with Basement Membranes" will determine whether or not EB affects cell-cell or cell- matrix interactions and determine what role, if any, moesin, a heparin- binding receptor protein, may have in this process. Ultimately, we hope that these studies will lead to better understanding of the function of the basement membrane zone and to more effective therapeutic approaches to EB.